block

n.

"solid piece," c.1300, from Old French bloc "log, block" of wood (13c.), via Middle Dutch bloc "trunk of a tree" or Old High German bloh, from a common Germanic source, from PIE *bhlugo-, from *bhelg- "a thick plank, beam" (see balk).

Meaning "mould for a hat" is from 1570s. Slang sense of "head" is from 1630s. Extended sense of "obstruction" is first recorded 1640s. In cricket from 1825; in U.S. football from 1912. The meaning in city block is 1796, from the notion of a "compact mass" of buildings; slang meaning "fashionable promenade" is 1869.

BLOCK. A term applied in America to a square mass of houses included between four streets. It is a very useful one. [Bartlett]

v.

"obstruct," 1590s, from French bloquer "to block, stop up," from Old French bloc (see block (n.)). Meaning "to make smooth or to give shape on a block" is from 1620s. Stage and theater sense is from 1961. Sense in cricket is from 1772; in U.S. football from 1889. Related: Blocked; blocking.

(blŏk) An arrangement of pulleys and ropes used to reduce the amount of force needed to move heavy loads. One pulley is attached to the load, and rope or chains connect this pulley to a fixed pulley. Each pulley may have multiple grooves or wheels for the rope to pass over numerous times. Pulling the rope or chain slowly draws the load-bearing pulley toward the fixed one with high mechanical advantage.